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Volkswagen Rabbit, Jetta, Scirocco, Convertible: 1975-1984 (A1) V-belt tensioning specs


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Last Post: Jan 21, 2014 6:06 PM Last Post By: tcovenant2000
aardvaark

Posts: 54
Registered: 05/14/05
V-belt tensioning specs
Posted: Jan 15, 2014 9:30 PM
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Attachment belts002.jpg (142.9 KB)
1984.5 Scirocco with A/C and PS.
A/C compressor sits below the alternator.
A/C and PS use tensioner bolts not shims.

Car has 3 belts as shown in image. The 84 and 85 Bentley, and 84 Haynes, all reference belt layouts different from that, and give various numbers for deflection. I compiled them all and here's what I think should be ok for my car:

alternator.....1/8" - 3/16"
crank-A/C......1/4" - 3/8"
crank-PS.......3/8" - 7/16"

Is that about right?
aardvaark

Posts: 54
Registered: 05/14/05
Re: V-belt tensioning specs
Posted: Jan 17, 2014 10:02 PM   in response to: aardvaark in response to: aardvaark
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Nevermind. I went ahead and just tightened them by feel as I usually do, until the pulleys they are driving won't turn by hand under the belt, and then a wee bit more. My main concern was getting them too tight which would cause premature bearing wear as Bentley warns.
tcovenant2000

Posts: 1,775
Registered: 12/09/03
Re: V-belt tensioning specs
Posted: Jan 19, 2014 4:28 PM   in response to: aardvaark in response to: aardvaark
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Yeah. Sorry I didn't reply, but had nothing to say. I've been tightening belts by hand and by feel for 45+ years and to my knowledge I haven't had any premature wear. The real issue, though, isn't with premature wear on the belts. It's with premature wear on the bearings. Overloading the bearings with horizontal stress is hard on them.

Thomas
aardvaark

Posts: 54
Registered: 05/14/05
Re: V-belt tensioning specs
Posted: Jan 19, 2014 10:07 PM   in response to: tcovenant2000 in response to: tcovenant2000
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Sorry I didn't reply, but had nothing to say.

I totally understand that. A sign of wisdom. :)

This forum won't allow deleting original posts, or I would have, after thinking about it a bit. I only got paranoid because I was lately reading Bentley and Haynes a lot and noticed the profusion of different numbers.

The last time I messed with the belts was in process of replacing the waterpump, which was a horrorshow of a long drawn out battle with weird brackets and stripped allen bolts. So I figured, merely changing the belts -- no problem, right. But no. In order to replace the alternator belt, the A/C belt has to be off the pulley. And in order to replace the A/C belt, the power steering pulley must be completely removed.

I am going to look into pulling that A/C compressor from the car. I never run the A/C, it eats power, so for me it's just extra weight and an extra belt to deal with.
tcovenant2000

Posts: 1,775
Registered: 12/09/03
Re: V-belt tensioning specs
Posted: Jan 20, 2014 6:33 PM   in response to: aardvaark in response to: aardvaark
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You're lucky to have the .5, then. The old skool (84.0 and earlier) had the alternator down and the compressor up, on a monstrous bracket, plus had shims for adjusting the belts. What a nightmare.
With the .5 you can go all the way up to '98 or something (at least with cabbies and 'roccos, I think more like '92 with US made) and find brackets and pullies on cars without AC so you can relieve your car of that burden.
As I recall, forums.vwvortex.com has info on that exact mod. Maybe saw stuff here as well.

Thomas
aardvaark

Posts: 54
Registered: 05/14/05
Re: V-belt tensioning specs
Posted: Jan 21, 2014 11:36 AM   in response to: tcovenant2000 in response to: tcovenant2000
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Thomas I do have one more question about the A/C belt. When the A/C compressor is loosened it will only rotate down so far and then hits the water pump pulley. As a result the A/C belt won't just slip off, it must be rolled off the pulley by turning the crankshaft and gradually forcing the belt up over the pulley rim. Installation the same way, belt has to be rolled on to the pulley. This can't be good for the belt.

Did a forum search on it and found this old post by you ca. 2003:

Caterpillar Fan Belt

Appears you had the same problem with that car, did you ever find a solution?

Leo
tcovenant2000

Posts: 1,775
Registered: 12/09/03
Re: V-belt tensioning specs
Posted: Jan 21, 2014 6:06 PM   in response to: aardvaark in response to: aardvaark
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Nope. Never did. Still have the car. I've changed the belt once since then (due to age, not miles) and had to do the same thing. The problem I was having with the "Caterpillar belt" issue was related to the belt not being the right width or pitch. I finally tried another (more expensive) belt and it worked.

Thomas

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